JP6776359B2 - Multi-beam element backlighting with convergent view - Google Patents

Description

Cross-references of related applications This application claims the priority of US Provisional Patent Application No. 62/289239 filed January 30, 2016, which is incorporated herein by reference in its entirety.

No mention of federal-funded R & D

Electronic displays are almost ubiquitous media for communicating information to users of a wide variety of devices and products. The most commonly used electronic displays are cathode ray tubes (CRTs), plasma display panels (PDPs), liquid crystal displays (LCDs), electroluminescence displays (ELs), organic light emitting diodes (OLEDs) and active matrix OLEDs (AMOLEDs). ) Display, liquid crystal display (EP), and various displays utilizing electromechanical or electrofluid light modulation (eg, digital micromirror devices, electrowetting displays, etc.). In general, electronic displays can be classified as either active displays (ie, displays that emit light) or passive displays (ie, displays that modulate the light supplied by another light source). The most obvious examples of active displays are CRTs, PDPs, and OLEDs / AMOLEDs. The displays that are usually classified as passive when considering the emitted light are LCD and EP displays. Passive displays often exhibit attractive performance characteristics, such as, but not limited to, inherently low power consumption, but to some extent in many practical applications due to their inability to emit light. Use may be restricted.
To overcome the limitations of passive displays associated with light emission, many passive displays are coupled to an external light source. The combined light source may allow these displays, which are inherently passive, to emit light and effectively function as active displays. An example of such a coupled light source is a backlight. The backlight can function as a light source (often a panel backlight) that is placed behind a display that is inherently passive and illuminates the passive display. For example, the backlight can be coupled to an LCD or EP display. The backlight emits light that passes through the LCD or EP display. The emitted light is modulated by the LCD or EP display, and the modulated light is emitted from the LCD or EP display. Backlights are often configured to emit white light. In this case, color filters are used to convert the white light into the various colors used in the display. Color filters may be placed, for example, on the output of the LCD or EP display (less common) or between the backlight and the LCD or EP display.

Various features of examples and embodiments according to the principles described herein can be more easily understood by reference to the following detailed description in association with the accompanying drawings. In these drawings, the same reference numbers refer to the same structural elements.

FIG. 1A is a perspective view showing a multi-view display according to an embodiment according to the principle described in the present specification. FIG. 1B is a diagram showing an angular component of a ray having a specific principal angular direction corresponding to the viewing direction of a multi-view display according to an embodiment according to the principle described herein. .. It is sectional drawing which shows the diffraction grating in an Example by embodiment by the principle described in this specification. It is sectional drawing which shows the multi-view backlight in an Example by embodiment by the principle described in this specification. FIG. 3B is a plan view showing a multi-view backlight according to an embodiment according to the principle described in the present specification. FIG. 3C is a perspective view showing a multi-view backlight according to an embodiment according to the principle described in the present specification. It is sectional drawing which shows the multi-view backlight in an Example by embodiment by the principle described in this specification. FIG. 5 is a cross-sectional view showing a portion of a multi-view backlight comprising a multi-beam element in an embodiment according to an embodiment according to the principles described herein. FIG. 5 is a cross-sectional view showing a portion of a multi-view light including a multi-beam element in an embodiment according to another embodiment according to the principles described herein. FIG. 5 is a cross-sectional view showing a portion of a multi-view backlight comprising a multi-beam element in an example according to another embodiment according to the principles described herein. FIG. 5 is a cross-sectional view showing a portion of a multi-view backlight comprising a multi-beam element in an example according to another embodiment according to the principles described herein. FIG. 5 is a cross-sectional view showing a portion of a multi-view backlight comprising a multi-beam element in an example according to another embodiment according to the principles described herein. It is a block diagram which shows the multi-view display in an Example by embodiment by the principle described in this specification. It is a flow chart which shows the method of the multi-view backlight operation in an Example by embodiment by the principle described in this specification.

Certain embodiments and embodiments have other features in addition to or in place of the features shown in the drawings above. Hereinafter, these features and other features will be described with reference to the above drawings.

Examples and embodiments according to the principles described herein provide multi-view or three-dimensional (3D) displays and multi-view backlighting that is applied to multi-view displays that have or provide convergent views. In particular, embodiments according to the principles described herein provide multi-view backlighting that utilizes multi-beam elements configured to provide light rays with a plurality of different principal maximal angular directions. According to various embodiments, these different principal maximal angular directions of the rays provided by the multi-beam elements of the multi-view backlight correspond to different directions of various different views of the multi-view display. Moreover, according to various embodiments, the plurality of rays provided by each multi-beam element is tilted towards the center of the field zone of the multi-view display. When multi-view backlighting is used with a multi-view display, the tilt of multiple rays toward the center of the field of view zone results in different views of the display image that converge to the corresponding different positions across the field of view zone (ie, converged view). Bring). Applications for multi-view displays that utilize multi-view backlighting with convergent views are not limited, but are limited to mobile phones (eg smartphones), watches, tablet computers, mobile computers (eg laptop computers), personal computers and Includes computer monitors, automotive display consoles, camera displays, and a variety of other mobile and virtually non-mobile display applications and devices.

As used herein, a "multi-view display" is defined as an electronic display or electronic display system configured to provide different views of a multi-view image (eg, views of different viewpoints) in different viewing directions. .. FIG. 1A is a perspective view showing a multi-view display 10 according to an embodiment according to the principle described in the present specification. As shown in FIG. 1A, the multi-view display 10 includes a screen 12 for displaying a multi-view image to be viewed. The screen 12 can be the display screen of a telephone (eg, mobile phone, smartphone, etc.), tablet computer, laptop computer, desktop computer computer monitor, camera display, or electronic display of virtually any other device. it can. The multi-view display 10 provides various views 14 of the multi-view image in various viewing directions 16 with respect to the screen 12. The viewing direction 16 is shown as arrows extending from the screen 12 in various different main maximal angles. The various views 14 are shown as shaded polygons at the ends of their arrows (ie, the arrows indicating the viewing direction 16). FIG. 1A also shows only four views 14 and four viewing directions 16, all of which are for illustration purposes only and not for limitation purposes. Although various views 14 are shown in FIG. 1A as being above the screen, when the multi-view image is displayed on the multi-view display 10, these views 14 are actually on the screen 12 or Note that it appears in the vicinity of the screen 12. The view 14 is shown above the screen 12 for the sake of brevity, and the multi-view display 10 is viewed from each of these viewing directions 16 corresponding to a particular view 14. It is for expressing that.

The "field of view" of a multi-view display, that is, a ray having a direction corresponding to the direction of the field of view (ie, a directional ray), generally has a principal maximal angular direction given by the angular component {θ, φ} as defined herein. Have. The angular component θ is referred to herein as the "altitude component" or "elevation angle" of the ray. The angle component φ is called the “azimuth component” or “azimuth angle” of the light beam. By definition, elevation θ is an angle in a vertical plane (eg, a plane orthogonal to the plane of the multiview display screen) and azimuth φ is a horizontal plane (eg, a plane parallel to the plane of the multiview display screen). The angle inside.

FIG. 1B shows the angular component of a ray 20 having a specific principal maximal angular direction corresponding to the visual field direction (eg, visual field direction 16 of FIG. 1A) of the multi-view display according to an embodiment according to the principle described herein. It is an illustration of {θ, φ}. In addition, the light beam 20 is emitted or emitted from a particular point, as defined herein. That is, by definition, the ray 20 has a central radiation associated with a particular origin within the multiview display. FIG. 1B also shows the origin O of the light beam (or the viewing direction). The illustrated ray 20 may represent a directional ray.

In addition, the term "multi-view" as used in the terms "multi-view image" and "multi-view display" is defined as multiple views. The plurality of views, in some embodiments, may represent different perspectives or may include angular variation among the views of the plurality of views. Further, as used herein, the term "multi-view" specifies more than two different views (ie, at least three views, and generally more than three views) as defined herein. Including. Thus, the "multi-view display" used herein can be explicitly distinguished from a stereoscopic display that contains only two different views to represent a scene or image. However, while multi-view images and multi-view displays include more than two views as defined herein, multi-view images are only two of those multi-view views (eg, one view per eye). Can be viewed as a stereoscopic pair of images (eg, on a multi-view display) by choosing to view at once.

A "multi-view pixel" is defined herein as a set of pixels or "view pixels" that represent the respective image pixels of a plurality of similar different views of a multi-view display. In particular, a multi-view pixel has individual view pixels that correspond to the respective image pixels of the various views of the multi-view image or represent the respective image pixels of the various views of the multi-view image. Further, a view pixel of a multi-view pixel is a so-called "direction pixel" as defined herein because each view pixel is associated with a predetermined viewing direction of the corresponding view of the various views. Moreover, according to various examples and embodiments, the various view pixels represented by the view pixels of the multi-view pixels have equivalent, or at least substantially similar positions or coordinates, in each of the different views. Can have. For example, the first multi-view pixel may have an individual view pixel corresponding to the image pixel located at {x ₁ , y ₁ } in each of the various views of the multi-view image, and the second multi-view Pixels may have individual view pixels corresponding to image pixels located at {x ₂ , y ₂ } in each of the various views, and so on.

In some embodiments, the number of view pixels in a multi-view pixel may be equal to the number of views in a multi-view display. For example, a multi-view pixel may provide 64 view pixels associated with a multi-view display having 64 different views. In another example, a multi-view display may provide an 8x4 array of views (ie, 32 views), and the multi-view pixels may contain 32 view pixels (ie, one for each view). In yet another embodiment, some views of the multi-view display can extend from two or more views to virtually any part and are arranged in virtually any arrangement (eg, rectangle, circle, etc.). can do. Thus, view pixels in a multi-view pixel can, in some embodiments, have a similar number and array of views as the number and array of views in a multi-view display. Further, each of the different view pixels has a related direction (ie, the principal maximal angular direction of the ray) corresponding to a different one of the viewing directions corresponding to a different view (eg, 64 different views).

Further, according to some embodiments, the number of multi-view pixels in a multi-view display is substantially the number of pixels in various individual views of the multi-view display (ie, the pixels that make up the selected view). May be equal to. For example, if the view contains 640 x 480 view pixels (ie, the view has a 640 x 480 view resolution), the multi-view display can have 307,200 multi-view pixels. In another example, if the view contains 100 x 100 pixels, the multi-view display can contain a total of 10000 (ie 100 x 100 = 10000) multi-view pixels.

As defined herein, a "convergent view" of a multi-view display is the direction in which the view pixels that make up a particular view converge to a predetermined position within the field zone (or converging plane) of the multi-view display. Refers to a set or multiple views of a view. For example, view pixels may contain modulated rays. In a convergent view, all modulated rays corresponding to the view pixels of a particular convergent view have a direction that converges to a predetermined position in the visual field zone. A convergent view can provide the user with virtually all pixels of this particular view. That is, when the user's eye is located at a position in the visual field zone corresponding to a particular convergent view, the user's eye is substantially only relevant to that view as a result of the convergent view of the multi-view display. It may receive pixels and not other view-related pixels.

Further, by definition, a "field of view zone" is a spatial area, usually in front of a multi-view display, from which the image displayed by the multi-view display can be seen, eg, an image in which the user's eyes are displayed. It is an area that can be perceived, that is, "seen". Usually, this spatial region may be a plane at a predetermined distance (ie, viewing distance f) from the multi-view display, eg, a plane at a distance f from the screen of the multi-view display, or at least correspond to that plane.

In various embodiments according to the principles described herein, the viewing distance f or viewing position of the front viewing zone of a multi-view display having a convergent view depends on, or these, the particular application or application of the multi-view display. May be selected based on. For example, when a multi-view display with a convergent view is used as a display on a mobile phone (eg, a smartphone), the viewing distance f is about 20 centimeters (from the screen of the multi-view display or in front of the screen of the multi-view display). It can be between ~ 20 cm) and about 40 cm (~ 40 cm). In other embodiments, the viewing distance f is, but is not limited to, from about 40 centimeters (~ 40 cm) to about, such as when a multi-view display is used as a computer monitor (eg, a desktop monitor). It can be between 80 centimeters (~ 80 cm). In other application areas (eg, automotive dashboard displays), the viewing distance f can be between about 70 centimeters (~ 70 cm) and about 100 centimeters (~ 100 cm), or more.

As used herein, an "optical waveguide" is defined as a structure that guides light within it using total internal reflection. In particular, the optical waveguide can include a core that is substantially transparent at the operating wavelength of the optical waveguide. In various embodiments, the term "optical waveguide" generally refers to a dielectric that uses total internal reflection to guide light at the interface between the dielectric material of the optical waveguide and the material or medium surrounding the optical waveguide. Refers to an optical waveguide. By definition, the condition for total internal reflection is that the index of refraction of the optical waveguide is greater than the index of refraction of the surrounding medium adjacent to the surface of the optical waveguide material. In some embodiments, the optical waveguide may also include a coating in addition to, or instead of, the refractive index differences described above, in order to further promote total internal reflection. This coating can be, for example, a reflective coating. The optical waveguide can be any of several optical waveguides, including, but not limited to, flat plate waveguides or slab waveguides, and one or both strip waveguides. ..

Further, in the present specification, the term "flat plate" when used for an optical waveguide such as "flat plate optical waveguide" is sometimes referred to as a "slab" waveguide, which is a piecewise or differentially planar layer or sheet. Is defined as. In particular, a flat plate optical waveguide is defined as an optical waveguide configured to guide light in two substantially orthogonal directions defined by the top and bottom surfaces (ie, opposite surfaces) of the optical waveguide. Moreover, as defined herein, the top and bottom surfaces are separated from each other and may be substantially parallel to each other, at least in a differential sense. That is, within any differential compartment of the flat plate optical waveguide, the top and bottom surfaces are substantially parallel or coplanar.

In some embodiments, the flat plate optical waveguide is substantially flat (ie, limited to a flat surface), and thus the flat plate optical waveguide is a planar optical waveguide. In other embodiments, the flat plate optical waveguide may be curved in one dimension or two orthogonal dimensions. For example, a flat plate optical waveguide can be curved to one dimension to form a cylindrical flat plate optical waveguide. However, any curvature has a radius of curvature large enough to ensure that total internal reflection is maintained and light is guided within the flat plate optical waveguide.

As used herein, a "diffraction grating" is generally defined as a plurality of features (ie, diffraction features) arranged to provide diffraction of light incident on the grating. In some embodiments, the features may be arranged periodically or quasi-periodically. For example, a grating may contain multiple features (eg, multiple grooves or ridges on the surface of a material) arranged in a one-dimensional (1D) array. In another example, the grating can also be a two-dimensional (2D) array of features. The grating can also be, for example, a 2D array of bumps or holes on the surface of the material.

Therefore, as defined herein, a "diffraction grating" is a structure that provides diffraction of light incident on the diffraction grating. When light enters the grating from the optical waveguide, the resulting diffraction or diffractive scattering can result in a "diffractive coupling" in which the grating can combine the light emitted from the grating by diffraction. This diffraction or diffraction grating is sometimes referred to as "diffraction coupling". The grating also diverts the light or changes the angle of the light by diffraction (ie, at the diffraction angle). In particular, the light exiting the diffraction grating as a result of diffraction generally has a propagation direction different from the propagation direction of the light incident on the diffraction grating (that is, the incident light). The change in the direction of light propagation due to diffraction is referred to herein as "diffraction direction change". Therefore, it can be understood that the diffraction grating has a structure including a diffraction feature that diffractically changes the direction of the light incident on the diffraction grating, and when the light is incident from the optical waveguide, the diffraction grating is transmitted from the optical waveguide. The light can be diffractively externally coupled.

Further, as defined herein, the features of the grating are called "diffraction features" and are on the surface of the material, within the surface of the material, at the surface of the material (ie, the boundary between the two materials). It may be one or more of them. This surface may be, for example, the surface of an optical waveguide. Diffractive features are various structures that diffract light, such as, but not limited to, one or more of grooves, ridges, holes, and bumps on the surface, in, or on the surface. Any of these can be included. For example, a grating may include multiple substantially parallel grooves in the surface of the material. In another example, the grating may contain multiple parallel ridges that rise from the surface of the material. Diffractive features (eg grooves, ridges, holes, bumps, etc.) are, but are not limited to, sinusoidal profiles, square profiles (eg binary gratings), triangular profiles, and serrated profiles (eg blazed). It can have any of a variety of cross-sectional shapes or profiles that result in diffraction, including one or more of the gratings.

According to the various examples described herein, a diffraction grating (eg, a diffraction grating of a multi-beam element as described below) is used to diffract light from an optical waveguide (eg, a flat plate optical waveguide) as a light beam. Can be scattered or combined. In particular, the diffraction angle θ _m provided by the locally periodic diffraction grating or the locally periodic diffraction grating can be given by the mathematical formula (1).

Here, λ is the wavelength of light, m is the order of diffraction, n is the refractive index of the optical waveguide, d is the distance or spacing between the features of the diffraction grating, and θ ₁ is. The angle of incidence of light on the diffraction grating. For brevity, equation (1) assumes that the grating is adjacent to the surface of the optical waveguide and the index of refraction of the material outside the optical waveguide is equal to 1 (ie no _out = 1). doing. Generally, the diffraction order m is given as an integer. The diffraction angle θ _{m of the} light beam generated by the diffraction grating can be given by the mathematical formula (1) when the diffraction order is positive (for example, m> 0). For example, when the diffraction order m is equal to 1 (ie, m = 1), first-order diffraction is produced.

FIG. 2 is a cross-sectional view showing a diffraction grating 30 according to an embodiment according to the principle described in the present specification. For example, the diffraction grating 30 may be located on the surface of the optical waveguide 40. Further, FIG. 2 shows a light ray 20 incident on the diffraction grating 30 at an incident angle θ ₁ . The light ray 20 is an induced light ray in the optical waveguide 40. FIG. 2 also shows a ray 50 diffractically generated by the diffraction grating 30 as a result of the diffraction of the incident ray 20 and coupled to the outside. The light ray 50 has a diffraction angle θm (or “main maximum angle direction” in the present specification) given by the mathematical formula (1). The diffraction angle θm may correspond to, for example, the diffraction order “m” of the diffraction grating 30.

As defined herein, a "multi-beam element" is a backlight or display structure or element that produces light containing multiple rays. In some embodiments, the multi-beam element can be optically coupled to the optical waveguide of the backlight to provide light rays by externally coupling a portion of the light guided within the optical waveguide. In other embodiments, the multi-beam element is capable of producing light emitted as these rays (eg, may include a light source). Moreover, the rays of the plurality of rays produced by the multi-beam element have different principal maximal angular directions, as defined herein. In particular, by definition, one of the plurality of rays has a predetermined principal maximal angular direction that is different from the other rays of the plurality of rays.

In addition, the plurality of rays can represent a light field. For example, a plurality of rays may be confined to a substantially conical spatial region, or may have a predetermined angular width including various principal maximal angular directions of the plurality of rays. Thus, a given angular width (ie, a plurality of rays) of the sum of these rays can represent a light field. According to various embodiments, the various principal maximal angular directions of the various rays are determined by features such as, but not limited to, the size of the multi-beam element (eg, length, width, area, etc.). Will be done. In some embodiments, the multi-beam element can be thought of as an "extended point light source", i.e., multiple point light sources distributed over the range of the multi-beam element, as defined herein. Further, the light beam produced by the multi-beam element has a principal maximal angular direction given by the angular component {θ, φ}, as defined herein with reference to FIG. 1B.

As defined herein, a "multi-beam diffraction grating" is a diffraction grating that produces a plurality of rays. In some embodiments, the multi-beam grating may be a "chirp" grating or include a "chirp" grating. The plurality of light rays generated by the multi-beam diffraction grating may have different main maximum angular directions represented by the angular components {θ, φ} as described above. In particular, according to various embodiments, each of these rays may have a predetermined principal maximal angular direction as a result of the diffractive coupling and diffractive redirection of the incident light by the multi-beam diffraction grating. For example, a multi-beam grating may generate eight rays in eight different major directions. According to various embodiments, the different principal maximal angular directions of the various rays are the pitch or spacing of the grating and the features of the multi-beam grating at the origin of each ray with respect to the direction of propagation of the incident light into the multi-beam grating. Determined by the combination with orientation or rotation.

As used herein, a "collimator" is defined as a substantially arbitrary optical device or device configured to collimate light. For example, a collimator may include, but is not limited to, a collimator mirror or reflector, a collimator lens, and various combinations thereof. In some embodiments, the collimator, including a collimator reflector, may have a reflective surface characterized by a parabolic curve or parabolic shape. In another example, the collimated reflector may include a molded parabolic reflector. "Molded parabolic" means that the curved reflective surface of the molded parabolic reflector deviates from the "true" parabolic curve so that it is determined to achieve a given reflection characteristic (eg, collimation). It means that you are doing it. Similarly, collimating lenses may include spherical surfaces (eg, biconvex spherical lenses).

In some embodiments, the collimator can be a continuous reflector or a continuous lens (ie, a reflector or lens with a substantially smooth continuous surface). In other embodiments, the collimating reflector or collimating lens may include, but is not limited to, a substantially discontinuous surface, such as a Fresnel reflector or Fresnel lens that provides a collimation of light. According to various embodiments, the collimator provided by the collimator may vary to a predetermined degree or amount depending on the embodiment. In addition, the collimator can be configured to provide collimators in one or both of the two orthogonal directions (eg, vertical and horizontal). That is, the collimator may include one or both of the two orthogonal directions that provide a collimator of light, according to some embodiments.

As used herein, a "collimation factor" is defined as the degree to which light is collimated. In particular, the collimation factor, as defined herein, defines the angular width of light radiation within the collimated ray. For example, the sigma factor σ specifies that most of the light radiation in the collimated ray is within a certain angular width (eg ± σ degrees around the center of the collimated ray or the direction of the principal maximal angle). can do. The light radiation of the collimated ray may have a Gaussian distribution with respect to the angle, and the angular width is at an angle determined by half the peak intensity of the collimated ray, according to some embodiments. There may be.

As used herein, a "light source" is defined as a source of light (eg, a light emitter configured to generate and emit light). For example, the light source may include a light emitter such as a light emitting diode (LED) that emits light at startup or on. In particular, in the present specification, the light source is not limited to these, but a light emitting diode (LED), a laser, an organic light emitting diode (OLED), a polymer light emitting diode, a plasma type light emitter, a fluorescent lamp, an incandescent lamp, and the like. And can be a substantially arbitrary illuminant, including one or more of substantially any other light source, or can include such substantially any illuminant. The light produced by the light source may have a color (ie, may contain light of a specific wavelength) or may contain a range of wavelengths (eg, white light). In some embodiments, the light source may include multiple illuminants. For example, a light source is a set of light emitters in which at least one of them produces light having a color or wavelength different from the color or wavelength of light produced by at least one of the other light emitters. Or it may include a group. These different colors may include, for example, primary colors (eg, red, green, blue).

In addition, the article "a" as used herein is intended to have its usual meaning in patented art, i.e., "one or more." For example, "multi-beam element" means one or more multi-beam elements, and thus "this multi-beam element" also means "this (s) multi-beam element" herein. ing. Also, in this specification, "top", "bottom", "upper", "lower", "upper", "lower", "front", "rear", "first", "second", "second", " Neither of these references to "left" or "right" is intended to be limiting herein. As used herein, the term "about" as used for a value generally means within the tolerance of the equipment used to produce that value, or is not explicitly specified. As long as it can mean plus or minus 10%, plus or minus 5%, or plus or minus 1%. Further, the term "substantially" as used herein means most, almost all, all, or amounts in the range of about 51% to about 100%. Moreover, the examples herein are for illustration purposes only and are provided for illustration purposes only.

According to some embodiments of the principles described herein, a multi-view backlight is provided. FIG. 3A is a cross-sectional view showing a multi-view backlight 100 according to an embodiment according to the principle described in the present specification. FIG. 3B is a plan view showing the multi-view backlight 100 according to the embodiment according to the principle described in the present specification. FIG. 3C is a perspective view showing a multi-view backlight 100 according to an embodiment according to the principle described in the present specification. The perspective view of FIG. 3C is shown partially cut out for ease of description herein.

The multi-view backlight 110 shown in FIGS. 3A to 3C is configured to provide a plurality of inclined rays (externally coupled rays) 102 (for example, as a light field) having different main maximum angular directions. The plurality of tilted rays 102 provided are directed away from the multi-view backlight 100 in different principal maximal directions corresponding to the respective viewing directions of the plurality of views of the multi-view display, according to various embodiments. Be done. In some embodiments, a plurality of rays 102 of the plurality of inclined rays 102 are modulated (eg, using a light valve as described below) to facilitate the display of information having 3D content. Can be done.

Further, according to various embodiments, the plurality of tilted rays 102 have a tilt towards the center of the visual field zone of the multi-view display. This tilt can be defined or characterized, for example, in a direction orthogonal to or away from the surface of the multi-view backlight 100. The tilt towards the center of this visual field zone is set to provide a convergent view of the multi-view display within or into the visual field zone. According to some embodiments, the central axes of the plurality of tilted rays 102 are set by this tilt so as to intersect the center of the visual field zone. In particular, the central axes of the plurality of tilted rays 102 provided by the multi-view backlight 100 can be directed toward the center of the visual field zone by the respective tilts of the plurality of tilted rays 102, and thus intersect with each other. Can be done.

As shown in FIGS. 3A to 3C, the multi-view backlight 110 includes an optical waveguide 110. The optical waveguide 110 can be, for example, a flat plate optical waveguide. The optical waveguide 110 is configured to guide light as guided light 104 along the length of the optical waveguide 110. For example, the optical waveguide 110 can include a dielectric material configured as an optical waveguide. The dielectric material can have a first index of refraction that is greater than the second index of refraction of the medium surrounding the dielectric optical waveguide. This difference in refractive index is set to promote total reflection of the induced light 104, for example, depending on one or more waveguide modes of the optical waveguide 110.

In some embodiments, the optical waveguide 110 can be a slab or flat plate optical waveguide that includes a stretched, substantially planar sheet of optically transparent dielectric material. A substantially planar sheet of dielectric material is configured to induce guided light 104 using total internal reflection. According to various examples, the optically transparent material of the optical waveguide 110 is not limited to these, but various types of glass (eg silica glass, alkali aluminosilicate glass, borosilicate glass, etc.). One or more of these, and any of a variety of dielectric materials, such as substantially optically transparent plastics or polymers (eg, polymethyl methacrylate or "acrylic glass", polycarbonate, etc.). Or it can be configured by either. In some embodiments, the optical waveguide 110 may further include a cladding layer (not shown) on at least a portion of the surface of the optical waveguide 110 (eg, one or both of the top and bottom surfaces). According to some embodiments, the cladding layer can be used to further promote total internal reflection.

Further, according to some embodiments, the optical waveguide 110 is a first surface 110'(eg, "front" surface or side) and a second surface 110'' (eg, "rear" surface or side) of the optical waveguide 110. It is configured to guide the guided light 104 by total internal reflection at a non-zero propagation angle between the sides). In particular, the induced light 104 propagates by reflecting or "bounding" between the first surface 110'and the second surface 110' of the optical waveguide 110 at a non-zero propagation angle. In some embodiments, including the various colors of light, a plurality of induction light rays induced light 104, with the corresponding angle of non-zero propagation angle specific to different colors, it is induced by the optical waveguide 110 Can be done. It should be noted that the non-zero propagation angle is not shown in FIGS. 3A to 3C for the sake of brevity. However, the thick arrow indicating the propagation direction 103 indicates the approximate propagation direction of the guided light 104 along the entire length of the optical waveguide of FIG. 3A.

The "non-zero propagation angle" as defined herein is the angle relative to the surface of the optical waveguide 110 (eg, the first surface 110'or the second surface 110'). Moreover, the non-zero propagation angle is greater than zero and less than the critical angle of total internal reflection within the optical waveguide 110, according to various embodiments. For example, the non-zero propagation angle of the guided light 104 can be between about 10 degrees and about 50 degrees, in some cases between about 20 degrees and about 40 degrees, or about 25 degrees. It can be between degrees and about 35 degrees. For example, the non-zero propagation angle can be about 30 degrees. In another example, the non-zero propagation angle can be about 20 degrees, or about 25 degrees, or about 35 degrees. Further, in certain embodiments, a particular non-zero propagation angle (eg, optionally) is selected as long as its non-zero propagation angle is chosen to be less than the critical angle of total internal reflection within the optical waveguide 110. Can be done.

The guided light 104 in the optical waveguide 110 can be introduced or coupled to the optical waveguide 110 at a non-zero propagation angle (eg, about 30-35 degrees). The input end of the optical waveguide 110 with one or more of a lens, mirror or similar reflector (eg tilted collimating reflector), and prism (not shown), eg, guiding light at a non-zero propagation angle as guided light 104. It can be easily introduced or combined into the part. When introduced into the optical waveguide 110, the induced light 104 propagates along the optical waveguide 110 in a direction that can generally be separated from the input end (for example, the direction indicated by the bold arrow in the direction along the x-axis of FIG. 3A). To do.

Further, the guided light 104, that is, the guided light 104 generated by incident light on the optical waveguide 110 may be a collimating ray according to various embodiments. As used herein, a "collimation light" or "collimation ray" is generally defined as a ray whose radiation is substantially parallel to each other within that ray (eg, guided light 104). In addition, light radiation diverging or scattering from collimation rays is not considered part of the collimation rays by definition herein. In some embodiments, the multi-view backlight 110 includes a collimator (eg, a tilted collimator) such as a lens, reflector or mirror as described above, capable of collimating light from, for example, a light source. .. In some embodiments, the light source comprises a collimator. The collimation light supplied to the optical waveguide 110 is the guided light 104 to be collimated. In various embodiments, the guided light 104 can be collimated according to or to have a collimating factor, as described above.

In some embodiments, the optical waveguide 110 may be configured to "recycle" the induced light 104. In particular, the guided light 104 guided along the entire length of the optical waveguide may be redirected along the length to a different propagation direction 103'that is different from the propagation direction 103. For example, the optical waveguide 110 may include a reflector (not shown) at the end of the optical waveguide 110 on the opposite side of the input end adjacent to the light source. The reflector can be configured to reflect the guided light 104 as recycled guided light toward the input end and return it. By recycling the induced light 104 in this way, the brightness of the multi-view backlight 110 (for example, the intensity of the light ray 102) is increased by allowing the multi-beam element to be used a plurality of times as described below. be able to.

In FIG. 3A, a bold arrow (eg, pointing in the negative x direction) indicating another propagation direction of the recycled induction light indicates the overall propagation direction 103'of the recycled induced light in the optical waveguide 110. Alternatively (for example, with respect to recycled induction light), or by introducing light into the optical waveguide 110 in another propagation direction 103'(in addition to, for example, the induction light 104 having propagation direction 103), in another propagation direction 103'. Propagating guided light 104 can also be provided.

As shown in FIGS. 3A to 3C, the multi-view backlight 100 has a plurality of multi-beam elements 120 that are separated from each other along the length of the optical waveguide 110, for example, in the propagation direction of the induced light 104 as shown in the drawing. Including further. In particular, the plurality of multi-beam elements 120 are separated from each other at finite intervals and represent individual separate elements along the overall length of the optical waveguide. That is, as defined herein, the plurality of multi-beam elements 120 are separated from each other according to a finite (ie, non-zero) inter-element distance (eg, a finite inter-center distance). Moreover, the plurality of multi-beam elements 120 generally do not touch each other, such as intersecting or overlapping, according to some embodiments. Therefore, each of the plurality of multi-beam elements 120 is generally separate and separate from the other multi-beam elements 120.

According to some embodiments, the plurality of multi-beam elements 120 may be arranged in either a one-dimensional (1D) array or a two-dimensional (2D) array. For example, the plurality of multi-beam elements 120 can be arranged as a linear 1D array. In another embodiment, the plurality of multi-beam elements 120 can be arranged as a rectangular 2D array, a circular 2D array, a 2D hexagonal array, and the like. Moreover, this array (ie, a 1D or 2D array) can be a constant or uniform array in some examples. In particular, the inter-element distance (eg, center-to-center distance or spacing) between the multi-beam elements 120 can be substantially uniform or constant throughout the array. In another example, the inter-element distance between the multi-beam elements 120 may vary in one or both directions across the array and along the overall length of the optical waveguide 110.

According to various embodiments, the plurality of multi-beam elements 120 are configured to externally couple a portion of the guided light 104 as a plurality of tilted rays 102. In particular, FIGS. 3A and 3C show the plurality of inclined rays 102 as a plurality of diverging arrows pointing away from the first surface (or front surface) 110'of the optical waveguide 110. Further, as described above and as shown in FIG. 3A, the plurality of tilted rays 102 externally coupled by the multi-beam element 120 have slopes that direct the plurality of tilted rays to the center or central portion of the visual field zone. In FIG. 3A, this inclination is indicated by an inclination angle φ. It should be noted that the plurality of tilted rays 102 associated with each multi-beam element 120 have different slopes that direct each of the plurality of tilted rays toward the center of the visual field zone. Therefore, this tilt or tilt angle φ starts from substantially zero in the case of the multi-beam element 120 at or near the center point of the multi-view backlight 100, and from the center of the multi-view backlight, for example, as shown in FIG. 3A. It may vary or extend beyond zero on both sides apart.

3A-3C also further show an array of light valves 108 configured to modulate the light rays 102 of a plurality of gradient rays. The light valve array can be part of a multi-view display utilizing, for example, a multi-view backlight, which is shown in FIGS. 3A-3C together with the multi-view backlight 100 for ease of description herein. There is. As mentioned above, the array of light valves 108 shown in FIG. 3C is partially cut out so that the optical waveguide 110 and the multi-beam element 120 underneath the light valve array can be seen.

As shown in FIGS. 3A to 3C, different light rays 102 of a plurality of gradient rays having various principal maximal directions can pass through and modulate different light valves 108 in the light valve array. it can. Further, as shown, the light valve 108 of the array corresponds to the view pixel 106', and the set of these light valves 108 corresponds to the multi-view pixel 106 of the multi-view display. In particular, different sets of light valves 108 in the light valve array receive and modulate a plurality of gradient rays 102 from each of the different multi-beam elements 120, i.e., for each multi-beam element 120, as shown. There is one unique set of light valves 108. In various embodiments, various different types of light valves include, but are not limited to, liquid crystal light valves, electrophoretic light valves, and one or more of electrowetting-based light valves. , Can be used as the light valve 108 of the light valve array.

In FIG. 3A, the first light valve set 108a is configured to receive and modulate a plurality of inclined light rays 102 from the first multi-beam element 120a, and the second light valve set 108b is a second multi-beam. It is configured to receive and modulate a plurality of inclined light rays 102 from the beam element 120b. Therefore, each light valve set in the light valve array (eg, first light valve set 108a and second light valve set 108b) corresponds to a different multi-view pixel 106 and is an individual light valve 108 of the light valve set. Corresponds to the view pixel 106'of each multi-view pixel 106.

In various embodiments, the relationship between the plurality of multi-beam elements 120 and the corresponding multi-view pixels 106 (eg, a set of light valves 108) is a one-to-one relationship. That is, there are the same number of multi-view pixels 106 and the same number of multi-beam elements 120. FIG. 3B shows a one-to-one relationship for illustration purposes, where each multiview pixel 106 containing different sets of light valves 108 is shown surrounded by a dashed line. In other embodiments (not shown), the number of multi-view pixels 106 and the number of multi-beam elements 120 may differ from each other.

Further (eg, as shown in FIG. 3A), each multi-beam element 120 can be configured to provide a plurality of tilted rays 102 to only one multi-view pixel 106. In particular, for a given one of the multi-beam elements 120, the rays 102 of the plurality of tilted rays having different principal maximal angular directions corresponding to different views of the multi-view display are substantially as shown in FIG. 3A. Limited to a single corresponding multi-view pixel 106 and its view pixel 106', i.e. a set of single light valves 108 corresponding to its multi-beam element 120. Thus, each multi-beam element 120 of the multi-view backlight 100 provides a corresponding plurality of tilted rays 102 (ie, this set, or a set of different principal maximal angular directions corresponding to different views of the multi-view display). The plurality of inclined rays 102 include rays having directions corresponding to each of different viewing directions).

According to various embodiments, the deviation (eg, lateral deviation) of the multi-beam element 120 of the multi-beam element array with respect to the position of the corresponding multi-view pixel 106 is set to provide the inclination of the plurality of tilted rays 102. Will be done. In particular, the inter-element distance (eg, center-to-center distance) between a pair of multi-beam elements 120 is greater than the inter-pixel distance (eg, center-to-center distance) between a pair of corresponding multi-view pixels 106 in a multi-view display. There is. The larger inter-element distance than the inter-pixel distance can provide a shift of the multi-beam element 120 with respect to the corresponding multi-view pixel 106. In other words, the inter-element distance to inter-pixel distance ratio can be set to provide the tilt of the plurality of tilted rays 102 towards the center of the visual field zone.

As shown in FIGS. 3A and 3B, the center-to-center distance d (that is, the inter-element distance) between the first multi-beam element 120a and the second multi-beam element 120b is the first light valve set 108a and the second. The center-to-center distance D (ie, the inter-pixel distance) between the light valve sets 108b of the above (ie, d> D). Note that in FIGS. 3A and 3B, the light valve sets 108a, 108b represent a pair of multi-view pixels 106 corresponding to the multi-beam elements 120a, 120b. Since the inter-element distance d is larger than the inter-pixel distance D, the multi-beam element 120 is displaced from the corresponding multi-view pixel 106. This shift provides the tilt of the plurality of tilted rays 102 (ie, resulting in a tilt angle φ), as shown in FIG. 3A. Therefore, the tilt or tilt angle φ can be directly controlled by appropriately selecting this deviation, according to various embodiments.

In some embodiments, the multi-beam element 120 has a scattering property configured to provide the tilt of the plurality of tilted rays 102 towards the center of the visual field zone. For example, each multi-beam element 120 of the multi-beam element array adjusts the emission pattern of the multi-beam element 120 and provides a tilt, i.e. the corresponding scattering set to provide the tilt emission pattern of the multi-beam element 120. May have properties. This scattering property may include, but is not limited to, diffraction (eg, provided by the spacing or pitch of the grating), reflection, refraction provided by the multi-beam element 120, for example. The corresponding scattering characteristics of each multi-beam element 120 may vary depending on, for example, the position of each multi-beam element 129 in the array along the overall length of the optical waveguide.

In some embodiments, the corresponding scattering properties, which vary with position, are set to further tilt the plurality of tilted rays towards the center of the visual field zone in addition to the tilt provided by the shifts described above. To. In other embodiments (not shown), this tilt is provided by the scattering properties of the multi-beam element 120, between the pair of multi-beam elements 120 and the relative center of the corresponding light valve set or multi-view pixel 106. The distances can be substantially equal, for example, the multi-beam element 120 has approximately the same inter-element spacing (ie, center-to-center distance d) as the spacing between light valve sets representing the multi-view pixel 106 (ie, center-to-center distance D). ) May have. Further, the tilt provided by the position-varying scattering properties (eg, the emission pattern tilt) is the brightness uniformity of the multi-view backlight 100, eg, the rays 102 of the plurality of gradient rays 102, or within those rays 102. May result in one or both of improved and improved color uniformity.

According to some embodiments, different views within the plurality of views of the multi-view display have their respective field positions within the field zone. That is, different views may appear at different locations within the visual field zone. Further, the rays of the plurality of rays corresponding to each of the different views can be set to intersect the field zone at each field position to provide a convergent view, depending on the tilt. Convergent views can reduce or substantially eliminate optical aberrations or visual artifacts such as spatial rainbows and dark fringes that correspond to transitions between views. Convergent views can also provide view uniformity that represents a multi-view image displayed by a multi-view display.

FIG. 4 is a cross-sectional view showing a multi-view backlight 100 according to an embodiment according to the principle described in the present specification. In particular, the multi-view backlight 100 shown in FIG. 4 includes an optical waveguide 110 and a multi-beam element 120. An array 109 of light valves 108 divided into multi-view pixels 106 is also shown. The dashed line at a distance f from the light valve array 109 represents, for example, the field of view zone 140 of a multi-view display. The distance f from the light valve array 109 to the viewing zone 140 may be the target viewing distance of the multi-view display including the light valve array 109 and the multi-view backlight 100. Further, the view of the multi-view display at the positions indicated by A, B, C, D, E, F, G, and H is shown within the field of view zone 140.

According to some embodiments, the target viewing distance may be the best viewing distance determined by the field of application of a multi-view display with a built-in multi-view backlight 100 having a converging views. In particular, the target viewing distance or distance f can be a position where the user's eyes are expected to be placed to view the multi-view display. In some embodiments, for example, when a multi-view display is used in a mobile device such as, but not limited to, a mobile phone (eg, a smartphone) or a tablet computer, the distance f is from about 20 cm to about. It can be between 40 cm. In other embodiments, for example, but not limited to, in applications such as, but not limited to, computer monitors or automotive displays (eg, automotive dashboards or console displays), distance f is between 30 cm and about 120 cm. Can be in between.

As shown in FIG. 4, the rays 102 of the plurality of inclined rays 102 are externally coupled from the optical waveguide 110, pass through the multiview pixel 106, and are modulated by this. The broken line of the inclination angle φ represents the central axis of the plurality of inclined rays 102 in FIG. As shown, the central axes of the plurality of inclined rays 102 intersect the visual field zone 140 at the visual field zone center 142. Further, as shown, the first rays 102a from each of the multi-beam elements 120 corresponding to the first view (eg, the first view at position A) intersect the visual field zone 140 at position A. Similarly, as shown in FIG. 4, the second rays 102b from each of the multi-beam elements 120 corresponding to the second view intersect the visual field zone 140 at position B and the multi corresponding to the third view. The third ray 102c from each of the beam elements 120 intersects the visual field zone 140 at position C, and so on. The intersecting rays 102a, 102b, and 102c form a convergent view at positions A, B, and C, respectively, within the visual field zone 140. Therefore, these convergent views can be seen by arranging the eyes at various visual positions within the visual field zone 140. Further, in FIG. 4, the central axes of the plurality of inclined rays 102 are shown.

According to some embodiments, the shape of the multi-beam element 120 is similar to the shape of the multi-view pixel 106, i.e. the shape of a set (or "sub-array") of light valves 108 corresponding to the multi-view pixel 106. Is similar to. For example, the multi-beam element 120 may have a square shape and the multi-view pixel 106 (or an array of corresponding sets of light valves 108) may be substantially square. In another example, the multi-beam element 120 may have a rectangular shape, i.e., may have a length or longitudinal dimension greater than the width or lateral dimension. In this embodiment, the multi-beam element 120 may have a rectangular shape. The corresponding multi-view pixel 106 (ie, an array of sets of light valves 108) may have a similar rectangular shape. FIG. 3B is a top view or plan view showing a square multi-beam element 120 and a corresponding square multi-view pixel 106 including a square set of light valves 108. In yet another example (not shown), the multi-beam element 120 and the corresponding multi-view pixel 106 include, but are not limited to, triangles, hexagons, and circles, or are at least approximated by them. Has various shapes.

Further, referring again to FIGS. 3A to 3C, according to some embodiments, the size of the multi-beam element 120 is equivalent to the size of the view pixel 106'in the multi-view pixel 106 of the multi-view display. Sometimes. As used herein, "size" can be defined in any of a variety of ways, including, but not limited to, length, width, area, and the like. For example, the size of the view pixel 106'may be that length, and a size equivalent to that of the multi-beam element 120 may also be the length of the multi-beam element 120. In another example, "size" may refer to the area so that the area of the multi-beam element 120 can be equal to the area of the view pixel 106'.

In some embodiments, the size of the multi-beam element 120 is comparable to the size of the view pixel so that the size of the multi-beam element is between about 50% and about 200% of the size of the view pixel. For example, when the size of the multi-beam element is represented by "s" and the size of the view pixel is represented by "S" (for example, shown in FIGS. 3A to 3C), the size s of the multi-beam element is calculated by the mathematical formula ( 2 ). Can be given at.
0.5S ≤ s ≤ 2S ( 2 )
In other embodiments, the size of the multi-beam element is greater than about 60% of the view pixel size, greater than about 70% of the view pixel size, greater than about 80% of the view pixel size, or about about the view pixel size. Over 90%, multi-beam elements are less than about 180% of the view pixel size, less than about 160% of the view pixel size, less than about 140% of the view pixel size, or about 120% of the view pixel size. Is less than. For example, "equivalent size" allows the size of the multi-beam element to be between about 75% and about 150% of the size of the view pixel. In another embodiment, the size of the multi-beam element 120 may be equivalent to the view pixel 106'when the size of the multi-beam element is between about 125% and about 85% of the size of the view pixel. it can. According to some embodiments, the equivalent size of the multi-beam element 120 and the view pixel 106'reduces duplication between views in a multi-view display, or minimizes in some embodiments. At the same time, it may be chosen to reduce the dark area between the views of the multi-view display, or to minimize it in some embodiments.

As shown in FIG. 3A, the size of the view pixel 106'may correspond to the size of the light valve 108 in the light valve array. In other embodiments, the size of the view pixel may be defined as the distance between adjacent light valves 108 in the light valve array (eg, the center-to-center distance). For example, the light valve 108 may be smaller than the center-to-center distance between the light valves 108 in the light valve array. The size of the view pixel can be defined as, for example, either the size of the light valve 108 or the size corresponding to the center-to-center distance between the light valves 108.

According to various embodiments, the multi-beam element 120 can include any of several different structures configured to externally couple or scatter a portion of the induced light 104. For example, these different structures may include, but are not limited to, diffraction gratings, microreflecting elements, microrefracting elements, or various combinations thereof. In some embodiments, the multi-beam element 120, including a diffraction grating, is configured to diffractically externally couple a portion of the induced light as a plurality of tilted rays 102 having various principal maximal angular directions. In other embodiments, the multi-beam element 120 comprising a micro-refractive element is configured to reflexively externally couple a portion of the induced light as a plurality of tilted rays 102, or the multi-beam element 120 including a micro refracting element. Is configured to externally couple a portion of the induced light as a plurality of gradient light rays 102, either by refraction or by refraction (ie, a portion of the induced light is refractively externally coupled).

FIG. 5A is a cross-sectional view showing a part of the multi-view backlight 100 including the multi-beam element 120 according to the embodiment according to the principle described in the present specification. FIG. 5B is a cross-sectional view showing a portion of the multi-view backlight 100 including the multi-beam element 120 according to another embodiment according to the principles described herein. In particular, FIGS. 5A-5B show the multi-beam element 120 of the multi-view backlight 100 including the diffraction grating 122. The diffraction grating 122 is configured to diffractically externally couple a part of the induced light 104 as a plurality of inclined light rays 102. The diffraction grating 122 includes a plurality of diffraction features spaced apart from each other by the diffraction feature spacing or the diffraction feature or the pitch of the grating configured to provide a diffractive outer coupling of a portion of the induced light. According to various embodiments, the spacing or grating pitch of the diffraction features of the grating 122 may be less than the wavelength (ie, less than the wavelength of the induced light).

In some embodiments, the diffraction grating 122 of the multi-beam element 120 may be located on or adjacent to the surface of the optical waveguide 110. For example, the diffraction grating 122 may be on or adjacent to the first surface 110'of the optical waveguide 110, as shown in FIG. 5A. The diffraction grating 122 located on the first surface 110'of the optical waveguide is a transmission mode diffraction grating configured to diffractically externally couple a part of the induced light as a light ray 102 through the first surface 110'. Can be done. In another example, as shown in FIG. 5B, the diffraction grating 122 may be located on the second surface 110 ″ of the optical waveguide 110 or adjacent to the second surface 110 ″. When located on the second surface 110 ″, the diffraction grating 122 can be a reflection mode diffraction grating. As a reflection mode diffraction grating, the diffraction grating 122 diffracts a part of the induction light and reflects a part of the diffracted induction light toward the first surface 110'as a diffractically externally coupled light 102. It is configured to emanate through the first surface 110'. In other embodiments (not shown), the diffraction grating may be located between the surfaces of the optical waveguide 110, for example as one or both of a transmission mode diffraction grating and a reflection mode diffraction grating.

In some embodiments described herein, the principal maximal angular directions of the plurality of inclined rays 102 may include the effect of refraction by the plurality of inclined rays 102 emitted from the optical waveguide 110 on the surface of the optical waveguide 110. Please note that there is. For example, FIG. 5B shows the refraction (ie, bending) of a plurality of inclined rays 102 due to a change in the refractive index when the plurality of inclined rays 102 exit through the first surface 110'for purposes of illustration, not limitation. ing. See also FIGS. 6A and 6B described below.

According to some embodiments, the diffraction features of the grating 122 may include one or both of grooves and ridges separated from each other. Grooves or ridges include the material of the optical waveguide 110 and may be formed, for example, on the surface of the optical waveguide 110. In another example, the groove or ridge may be composed of a material other than the material of the optical waveguide, for example a film or layer of another material on the surface of the optical waveguide 110.

In some embodiments, the grating 122 of the multi-beam element 120 is a uniform grating in which the spacing of the diffraction features is substantially constant or constant throughout the grating 122. In another embodiment, the diffraction grating 122 is a chirp diffraction grating. By definition, a "chirp" grating is a grating that indicates or has a diffraction interval (ie, lattice pitch) of diffraction features that varies over the width or length of the chirp grating.

In some embodiments, the chirp grating has or may indicate a chirp of diffraction feature spacing that changes linearly with distance. Therefore, a chirp grating is, by definition, a "linear chirp" grating. In other embodiments, the chirp grating of the multi-beam element 120 may exhibit a non-linear chirp of diffraction feature spacing. A variety of non-linear chirps can be used, such as, but not limited to, exponential chirps, logarithmic chirps, or other substantially non-uniform or random but monotonously varying chirps. Non-monotonic chirps such as, but not limited to, sinusoidal chirps or triangular or serrated chirps can also be used. Any combination of any of these types of chirps can also be used.

In some embodiments (not shown), the diffraction grating of the multi-beam element 120 may include a multi-beam diffraction grating. In some embodiments, the grating may include a plurality of gratings. By definition, the scattering properties of a multi-beam element 120, including a grating (eg, a grating 122), are that diffraction (eg, diffractive coupling or diffractive scattering) by the grating, from or through the grating. Including. For example, the phase function (eg, lattice pitch or diffraction feature spacing) can be set or adjusted to guide or tilt the emission pattern of light due to diffractive coupling towards the center of the visual field zone. In other words, the inclination of the plurality of inclined rays 102 can be provided (or controlled) by selecting an appropriate diffraction scattering characteristic of the diffraction grating 122. 5A-5B are diagrams showing an example of how the tilt is provided by the scattering characteristics (eg, diffractive scattering) of the multi-beam element 120 including the grating 122.

FIG. 6A is a cross-sectional view showing a portion of the multi-view backlight 100 including the multi-beam element 120 according to another embodiment according to the principles described herein. FIG. 6B is a cross-sectional view showing a portion of the multi-view backlight 100 including the multi-beam element 120 according to another embodiment according to the principles described herein. In particular, FIGS. 6A and 6B are diagrams showing various embodiments of the multi-beam element 120, including micro-reflective elements. The micro-reflective elements used as, or within the multi-beam element 120, are not limited to these, but are reflective utilizing reflective materials or reflective material layers (eg reflective metals). It may include a vessel or a reflector based on total internal reflection (TIR). According to some embodiments (eg, shown in FIGS. 6A-6B), the multi-beam element 120, including the microreflecting element, is located on the surface of the optical waveguide 110 (eg, a second surface 110''), or It may be located adjacent to its surface. In other embodiments (not shown), the microreflecting element may be located within the optical waveguide 110 between the first surface 110'and the second surface 110'.

For example, FIG. 6A shows a multi-beam element 120 that includes a micro-reflective element 124 with reflective facets (eg, a "prism-like" micro-reflective element) located adjacent to a second surface 110 ″ of the optical waveguide 110. ing. The facet of the illustrated prismatic microreflecting element 124 is configured to reflect (ie, reflexively couple) a portion of the induced light 104 out of the optical waveguide 110. The facets are beveled or tilted (ie, have a tilt angle) with respect to the propagation direction of the guided light 104, and can reflect, for example, a portion of the guided light to exit the optical waveguide 110. Facets may be formed using reflective material within the optical waveguide 110 (eg, as shown in FIG. 6A), according to various embodiments, or prisms on the second surface 110''. It may be the surface of a hollow cavity. When utilizing a prismatic cavity, in some embodiments, changes in the index of refraction on the surface of the cavity may result in reflection (eg, TIR reflection), or the surface of the cavity forming the facet is coated with a reflective material. And may bring about reflection.

In addition, FIG. 6A shows a pair of micro-reflective elements 124. The first micro-reflective element 124a of the micro-reflective element pair has a scattering property (eg, reflection) set to provide a greater than zero tilt, or "non-zero tilt," for the plurality of tilted rays 102. For example, the first microreflecting element 124a is shown as having an asymmetric facet that provides a non-zero slope. A second microreflecting element 124b with symmetric facets is also shown. The symmetric facets of the second microreflecting element 124b can be set to provide, for example, the slopes of a plurality of tilted rays 102 that are substantially equal to zero, as shown.

In another example, FIG. 6B shows a multi-beam element 120 that includes, but is not limited to, a micro-reflective element 124 that has a substantially smooth curved surface, such as a hemispherical micro-reflective element 124. .. The particular surface curvature of the microreflecting element 124 can be configured to reflect a portion of the induction light in various directions, for example, depending on the incident point on the curved surface with which the induction light 104 comes into contact.

As shown in FIGS. 6A and 6B, a portion of the induced light that is reflexively externally coupled from the optical waveguide 110 exits or emanates from the first surface 110'for purposes of illustration, but not limitation. Similar to the prismatic microreflecting element 124 of FIG. 6A, the microreflecting element 124 of FIG. 6B is a reflective material within the optical waveguide 110, or a second surface, as shown in FIG. It can be a cavity formed in 110'' (for example, a hemispherical cavity). FIG. 6B also shows a guided light 104 having two propagation directions 103, 103'(ie, indicated by thick arrows) for purposes of illustration, but not limitation. However, the induction light 104 having the propagation direction 103'is optional. Further, by definition, the scattering properties of the multi-beam element 120, including the micro-reflective element (eg, micro-reflective element 124), include reflection from that micro-reflective element. In FIG. 6B, for ease of explanation, not for limitation, the tilt or tilt angle of the plurality of tilted rays 102 is shown as being substantially equal to zero.

FIG. 7 is a cross-sectional view showing a portion of the multi-view backlight 100 including the multi-beam element 120 according to another embodiment according to the principles described herein. In particular, FIG. 7 shows a multi-beam element 120 that includes a micro-refractive element 126. According to various embodiments, the microrefractive element 126 is configured to refractively externally couple a portion of the induced light 104 from the optical waveguide 110. That is, as shown in FIG. 7, the microrefractive element 126 uses refraction (for example, for diffraction or reflection) so that a part of the induced light is externally coupled from the optical waveguide 110 as a plurality of inclined rays 102. It is composed.

The microrefractive element 126 can have various shapes, such as, but not limited to, hemispherical, rectangular, prismatic (ie, shapes with inclined facets). According to various embodiments, the microrefractive element 126 may extend or project from, for example, the surface of the optical waveguide 110 (eg, the first surface 110'), as shown, or a cavity in the surface (FIG. (Not shown). In addition, the microrefractive element 126 may also include material for the optical waveguide 110 in some embodiments. In other embodiments, the microrefractive element 126 may include another material that is adjacent to the surface of the optical waveguide or, in some examples, in contact with the surface of the optical waveguide. By definition, the scattering properties of a multi-beam element 120 that includes a micro-refractive element (eg, micro-refractive element 126) include refraction by that micro-refractive element. In FIG. 7, for the sake of brevity, not for limitation, the slopes or angles of slope of the plurality of tilted rays 102 are shown as being substantially equal to zero.

Referring again to FIG. 3A, the multi-view backlight 100 may further include a light source 130 in some embodiments. According to various embodiments, the light source 130 is configured to provide light guided through the optical waveguide 110 at a non-zero propagation angle. In particular, the light source 130 may be located adjacent to the inlet surface or end (input end) of the optical waveguide 110. In various embodiments, the light source 130 includes, but is not limited to, substantially any source of light, such as one or more light emitting diodes (LEDs) or lasers (eg, laser diodes). Can be done. In some embodiments, the light source 130 may include a illuminant configured to produce substantially monochromatic light having a narrow band spectrum represented by a particular color. In particular, the color of monochromatic light can be the primary color of a particular color space or color model (eg, red / green / blue or "RGB" color model). In another example, the light source 130 may be a substantially wide band light source configured to provide substantially wide band or multicolored light. For example, the light source 130 can provide white light. In some embodiments, the light source 130 may include a plurality of different illuminants configured to provide light of different colors. These different illuminants can be configured to provide light with different color-specific non-zero propagation angles of the induced light, corresponding to each of the different colors of light.

In some embodiments, the light source 130 may further include a collimator. The collimator may be configured to receive light that is not substantially collimated from one or more of the light emitters of the light source 130. The collimator is further configured to convert this substantially non-collimated light into collimating light. In particular, in some embodiments, the collimator has a non-zero propagation angle and is capable of providing collimating light that is collimated according to a predetermined collimating factor. Moreover, when utilizing light emitters of different colors, the collimator has a collimator with one or both of the different color-specific nonzero propagation angles and with different color-specific collimating factors. Can be configured to provide. As described above, the collimator is further configured to transmit the collimator light beam to the optical waveguide 110 and propagate it as guided light 104.

In some embodiments, the multi-view backlight 100 is configured to be substantially transparent to light in a direction passing through an optical waveguide 110 orthogonal to the propagation directions 103, 103'of the induction light 104. Orthogonal. In particular, in some embodiments, the optical waveguide 110 and the plurality of isolated multi-beam elements 120 allow light to illuminate the optical waveguide 110, and thus both the first surface 110'and the second surface 110''. Allows you to pass. Transparency can be increased, at least in part, by both the relatively small size of the multi-beam element 120 and the relatively large inter-element spacing of the multi-beam element 120 (eg, a one-to-one correspondence with the multi-view pixel 106). it can. Further, according to some embodiments, the multi-beam element 120 is substantially relative to light propagating orthogonally to the optical waveguide surfaces 110', 110'', especially when the multi-beam element 120 includes a diffraction grating. It can also be transparent.

According to some embodiments of the principles described herein, a multi-view display is provided. A multi-view display is configured to emit modulated rays as pixels in the multi-view display. In addition, the emitted modulated light can be preferentially directed towards multiple visual field directions and, more specifically, during multiple convergent views of the multi-view display. In some embodiments, the multi-view display is configured to provide or "display" a 3D or multi-view image. According to various embodiments, each of the different modulated rays of different orientations may correspond to individual pixels of different "views" associated with the multiview image. This different view can provide, for example, a "naked eye" (eg, autostereoscopic) representation of the information in a multiview image displayed by a multiview display.

FIG. 8 is a block diagram showing a multi-view display 200 according to an embodiment according to the principle described in the present specification. According to various embodiments, the multi-view display 200 is configured to display multi-view images according to different views in different viewing directions. In particular, modulated rays 202 emitted from the multi-view display 200 are used to display a multi-view image, which rays can correspond to pixels in different views (ie, view pixels). The modulated ray 202 is shown in FIG. 8 as an arrow exiting the multiview pixel 210. For purposes of illustration rather than limitation, dashed lines are used for the arrows of the modulated rays 202 emitted to emphasize that they are modulated.

The multi-view display 200 shown in FIG. 8 includes an array of multi-view pixels 210. The multi-view pixels 210 of this array are configured to provide a plurality of different views of the multi-view display 200 as convergent views. In particular, the tilt of the plurality of tilted rays is configured to direct the central axis of the plurality of tilted rays (ie, the central ray) to the center of the visual field zone of the multi-view display. According to various embodiments, the multi-view pixel 210 in this array comprises a plurality of light valves, i.e., a plurality of view pixels, configured to modulate a plurality of tilted rays 204 to produce an emission-modulated ray 202. Including. The emission modulation ray 202 represents a convergent view of the multi-view display 200.

In some embodiments, the multi-view pixel 210 is substantially similar to the set of light valves 108 in the array of light valves 108 described above in connection with the multi-view backlight 100. In particular, the view pixel of the multi-view pixel 210 may be substantially similar to the light valve 108 described above. That is, the multi-view pixel 210 of the multi-view display 200 may include a set of light valves (eg, a set of light valves 108), and the view pixels of the multi-view pixel 210 may include a set of light valves (eg, a single set). It may include a light valve 108).

As shown in FIG. 8, the multi-view display 200 further includes an optical waveguide 220. The optical waveguide 220 is configured to guide light as guided light along the length of the optical waveguide 220. In some embodiments, the optical waveguide 220 of the multi-view display 200 may be substantially similar to the optical waveguide 110 described above in connection with the multi-view backlight 100. In particular, the optical waveguide 110 is configured to guide light by total internal reflection. The optical waveguide 220 can be a flat plate optical waveguide in some embodiments.

According to various embodiments, the multi-view display 200 shown in FIG. 8 further includes an array of multi-beam elements 230. Each multi-beam element 230 of this array is configured to externally couple (or externally scatter) a portion of the induced light as a plurality of corresponding gradient rays 204. In particular, the multi-beam element 230 can be optically coupled to the optical waveguide to externally couple a portion of the induced light. In addition, a plurality of tilted rays 204 are provided by each multi-beam element to the corresponding multi-view pixel 210. The rays 204 of the plurality of inclined rays 204 have different main maximum angular directions from each other. Further, these different principal maximal angular directions of the rays 204 correspond to different viewing directions of the different convergent views of the multiview display 200. In various embodiments, different views of the plurality of views of the multi-view display 200 may have their respective viewing positions within the visual field zone. The rays of the plurality of tilted rays 204, corresponding to each of the different views, are configured to, according to some embodiments, intersect the visual field zone at their respective viewing positions to provide a convergent view. Can be done.

According to various embodiments, the tilt of the plurality of tilted rays 204 is of the scattering properties of the multi-beam element 230 and the inter-element distance or spacing between the multi-beam elements relative to the inter-pixel distance or spacing between the multi-view pixels 210. It can be provided or controlled by one or both. In particular, as described above in connection with the multi-view backlight 100, in some embodiments, the inter-element distance between a pair of multi-beam elements 230 is the corresponding pair of multi-view pixels in the multi-view display 200. It may be greater than the inter-pixel distance between 210. The inter-element distance greater than the inter-pixel distance is set (eg, selected) to provide the tilt or tilt angle of the plurality of tilted rays 204. In addition to this, or otherwise, the scattering properties of the multi-beam element 230 can be set to vary depending on the position of the multi-beam element 230 within the multi-beam element array. This varying scattering property can be set to provide, or at least increase, the tilt or tilt angle of the plurality of tilted rays 204, according to some embodiments. In particular, in some embodiments, both the ratio of the inter-pixel distance to the inter-pixel distance and the scattering properties that vary with the position of the multi-beam element 230 combine to provide tilt.

In some embodiments, the size of the multi-beam element 230 in the multi-beam element array is comparable to the size of the view pixels of the plurality of view pixels. For example, the size of the multi-beam element 230 may be greater than half the size of the view pixel and less than twice the size of the view pixel in some embodiments. Further, there may be a one-to-one correspondence between the multi-view pixels 210 of the multi-view pixel array and the multi-beam elements 230 of the multi-beam element array. Therefore, each view pixel in the multi-view pixel 210 may be configured to modulate a different one of the plurality of tilted rays 204 provided by the corresponding multi-beam element 230. Further, each multi-view pixel 210 may be configured to receive and modulate a ray 204 from only one multi-beam element 230, according to various embodiments.

In some embodiments, the multi-beam element 230 of the multi-beam element array may be substantially similar to the multi-beam element 120 of the multi-view backlight 100 described above. For example, the multi-beam element 230 may include a diffraction grating that is substantially similar to the diffraction grating 122 shown above in FIGS. 5A to 5B. In some embodiments, the grating may include a multi-beam grating, or a plurality of gratings. In another embodiment, the multi-beam element 230 may include micro-reflective elements that are substantially similar to the micro-reflective elements 124 shown above in FIGS. 6A-6B. In yet another embodiment, the multi-beam element 230 may include a micro-refractive element. The micro-refractive element may be substantially similar to the micro-refractive element 126 shown in FIG. 7 above.

Moreover, in some of these embodiments (not shown in FIG. 8), the multi-view display 200 may further include a light source. This light source provides light to an optical waveguide having a non-zero propagation angle, and in some embodiments, provides light collimated according to a collimation factor, eg, within a predetermined optical waveguide 220 of guided light. It may be configured to cause angular diffusion. According to some embodiments, the light source may be substantially similar to the light source 130 of the multi-view backlight 100 described above.

According to other embodiments of the principles described herein, a method of multi-view backlight operation is provided. FIG. 9 is a flow chart showing a method 300 of multi-view backlight operation in an embodiment according to an embodiment according to the principle described in the present specification. As shown in FIG. 9, the method 300 of operating the multi-view backlight includes a step (310) of guiding light along the length of the optical waveguide. In some embodiments, the light can be guided at a non-zero propagation angle (310). In addition, the guided light can be guided by collimating according to a predetermined collimation factor. According to some embodiments, the optical waveguide may be substantially similar to the optical waveguide 110 described above in connection with the multi-view backlight 100.

As shown in FIG. 9, the operation method 300 of the multi-view backlight uses a multi-beam element to externally couple a part of the induced light from the optical waveguide (320), and has a plurality of main maximum angular directions different from each other. It further includes a step of providing an oblique ray. In various embodiments, the principal maximal angular directions of the plurality of tilted rays correspond to the respective viewing directions of the multi-view display. The plurality of tilted rays also have a tilt toward the center of the field of view zone of the multi-view display to provide a convergent view. According to various embodiments, the central axes of the plurality of inclined rays are set to intersect the center of the visual field zone by the inclination. In the definition herein, for example, when the central ray itself does not exist in the plurality of inclined rays, the central axes of the plurality of inclined rays may represent or be equivalent to the central ray.

In some embodiments, the multi-beam element is substantially similar to the multi-beam element 120 of the multi-view backlight 100 described above. For example, the multi-beam element may be part of a plurality of multi-beam elements or an array of multi-beam elements. Further, in some embodiments, the multi-beam element may include one or more of a diffraction grating, a micro-reflecting element, and a micro-refractive element. In particular, according to some embodiments, the multi-beam element used in externally coupling the induced light (320) is optically coupled to the optical waveguide to diffractically externally couple a portion of the induced light. (320) May include a diffraction grating. This grating may be substantially similar to, for example, the grating 122 of the multi-beam element 120. In another embodiment, the multi-beam element may include a (320) micro-reflective element that is optically coupled to an optical waveguide to reflexively externally couple a portion of the induced light. For example, the microreflecting element may be substantially similar to the microreflecting element 124 described above in connection with the multi-beam element 120. In yet another embodiment, the multi-beam element may include a (320) micro-refractive element that is optically coupled to the optical waveguide to refractively externally couple a portion of the induced light. The micro-refractive element may be substantially similar to the micro-refractive element 126 of the multi-beam element 120 described above.

According to some embodiments, the size of the multi-beam element is equivalent to the size of the view pixel in the multi-view pixel of the multi-view display. For example, a multi-beam element can be more than half the size of a view pixel and less than twice the size of a view pixel.

In some embodiments (not shown), the method of operating the multi-view backlight 300 is greater than the inter-pixel distance between the corresponding pair of multi-view pixels in the multi-view display (eg, in an array of multi-beam elements). ) Further includes the step of providing the gradient of a plurality of gradient rays by selecting the inter-element distance between the pair of multi-beam elements. In some embodiments, the method 300 of operating the multi-view backlight provides the scattering properties of the multi-beam elements in the array of multi-beam elements arranged along the length of the optical waveguide to the multi-beam element array. It may further include a step of providing the gradient of a plurality of gradient rays by varying depending on the position of the beam element. In some embodiments, the method 300 selects the inter-element distance to be greater than the inter-pixel distance and changes the scattering properties of the multi-beam element depending on its position along the optical waveguide. Both include steps to provide the gradient of multiple gradient rays.

In some embodiments (not shown), method 300 of operating a multi-view backlight further comprises the step of providing light to an optical waveguide using a light source. The light provided has a non-zero propagation angle in the optical waveguide, and is collimated in the optical waveguide according to a collimation factor to provide a predetermined angle diffusion of the induced light in the optical waveguide, or both. There is, it may be induced light. In some embodiments, the light source may be substantially similar to the light source 130 of the multi-view backlight 100 described above.

In some embodiments, method 300 of operating a multi-view backlight further comprises a step (330) of modulating a plurality of gradient rays using a light valve configured as a multi-view pixel in a multi-view display. According to some embodiments, the light valve of a plurality of light valves or an array of light valves corresponds to a view pixel of a multi-view pixel. That is, the multi-beam element may have, for example, a size equivalent to the size of the light valve or the intercenter spacing between the light valves of the plurality of light valves. According to some embodiments, the plurality of light valves may be substantially similar to the array of light valves 108 and the multi-view backlight 100 described above with reference to FIGS. 3A-3C. In particular, different sets of light valves may correspond to different multi-view pixels, just as the first and second light valve sets 108a, 108b correspond to different multi-view pixels 106 as described above. Further, just as the light valve 108 corresponds to the view pixel 106'in the above description of FIGS. 3A to 3C, the individual light valves of the light valve array may correspond to the view pixels of the multi-view pixel. ..

The examples and embodiments of the multi-view backlight, the operation method of the multi-view backlight, and the multi-view display having the multi-view pixels including the view pixels have been described above. This multi-view backlight, method, and multi-view display utilizes multi-beam elements to provide multiple tilted rays for different views of a multi-view image. It should be understood that the above examples are merely exemplary of a number of specific examples that represent the principles described herein. It will be apparent to those skilled in the art that a number of other configurations can be easily devised without departing from the scope defined by the following claims.

10 Multi-view display 12 screen 14 views 16 viewing direction 20 rays 30 diffraction grating 40 optical waveguide 50 externally coupled rays 100 multi-view backlight 102 rays 106 multi-view pixels 108 light valve 110 optical waveguide 120 multi-beam element 122 diffraction grating 124 micro-reflection Element 126 Micro Refractive Element 130 Light Source 200 Multiview Display

Claims (25)

It ’s a multi-view backlight,
An optical waveguide configured to guide light,
An array of multi-beam elements spaced apart from each other along the length of the optical waveguide, with each multi-beam element of the array corresponding a portion of the guided light to different viewing directions for multiple views of the multi-view display. Includes an array of multi-beam elements configured to externally couple from the optical waveguide as a plurality of gradient rays with different principal maximal angular directions.
The plurality of tilted rays have an inclination toward the center of the visual field zone of the multi-view display to provide a convergent view, so that the central axes of the plurality of inclined rays intersect the center of the visual field zone by the inclination. Multi-view backlight set to. A lateral shift of the multi-beam elements of the array of multi-beam elements with respect to the position of the corresponding multi-view pixel in the multi-view display provides said tilt of the plurality of tilted rays towards the center of the viewing zone. The shift is provided by the inter-element distance between the multi-beam element pairs of the multi-beam element array that is greater than the inter-pixel distance between the corresponding pairs of multi-view pixels of the multi-view display. The multi-view backlight according to claim 1. Each multi-beam element in the array of multi-beam elements has a corresponding scattering characteristic set to further tilt the plurality of tilted rays towards the center of the field of view zone, said correspondence of the multi-beam element. The multi-view backlight according to claim 2, wherein the scattering characteristics of the light guide vary depending on the position of each multi-beam element in the array along the length of the light guide. The multi View backlight. Different views of the plurality of views of the multi-view display have their respective viewing positions within the field of view zone, and the rays of the plurality of tilted rays corresponding to each of the different views are due to the tilt. The multi-view backlight according to claim 1, wherein each visual position is set to intersect the visual field zone to provide the convergent view. 1. Multi-view backlight. The multi-view backlight according to claim 1, wherein the multi-beam element includes a diffraction grating configured to diffractically externally couple the portion of the induced light as the plurality of inclined rays. The multi-view backlight according to claim 7, wherein the diffraction grating includes a multi-beam diffraction grating. The multi-beam element comprises one or both of a micro-reflecting element and a micro-refractive element, the micro-refractive element is configured to reflexively externally couple a portion of the induced light, the micro-refractive element. The multi-view backlight according to claim 1, wherein a part of the induced light is refractively externally coupled. The multi-view backlight according to claim 1, further comprising a light source optically coupled to the input of the optical waveguide, wherein the light source is configured to provide the induced light. The multi-view backlight according to claim 10, wherein the induced light is provided by the light source, which has a non-zero propagation angle, is collimated according to a predetermined collimation factor, or both. The multi-view display including the multi-view backlight according to claim 1, wherein the multi-view display further includes an array of light valves configured to modulate a light beam of the plurality of gradient light rays. A multi-view display in which the light valves of the array correspond to view pixels and the set of light valves in the array of light valves corresponds to the multi-view pixels of the multi-view display. It ’s a multi-view display,
An array of multi-view pixels configured to provide a plurality of different views of the multi-view display as convergent views, wherein the multi-view pixels have a plurality of tilts having different principal maximal angles corresponding to the viewing directions of the different views. An array of multi-view pixels, including multiple light valves configured to modulate the rays,
An optical waveguide configured to guide light,
An array of multi-beam elements, including an array of multi-beam elements configured such that each multi-beam element of the array of multi-beam elements is configured to externally couple a portion of the induced light as said plurality of gradient rays. ,
A multi-view display in which the tilts of the plurality of tilted rays are set so that the central axes of the plurality of tilted rays are directed toward the center of the visual field zone of the multi-view display. Claimed that the inter-element distance between pairs of multi-beam elements greater than the inter-pixel distance between the corresponding pairs of multi-view pixels in the multi-view display is configured to provide the tilt of the plurality of tilted rays. Item 13. The multi-view display according to item 13. 14. Multi-view display described in. 13. The multi-view display according to claim 13, wherein the size of the multi-beam element is larger than half the size of the light valve among the plurality of light valves and smaller than twice the size of the light valve. It further comprises a light source configured to provide light guided by the optical waveguide, the guided light having a non-zero propagation angle, collimated according to a collimation factor, and the induction within the optical waveguide. 13. The multi-view display according to claim 13, which provides diffusion of light at a predetermined angle. 13. Multi-view display. A mobile device including the multi-view display according to claim 13, wherein the mobile device is one of a mobile phone, a display console of an automobile, a mobile computer, a tablet computer, or a wristwatch. This is how the multi-view backlight works.
The step of guiding light in the propagation direction along the length of the optical waveguide,
A step of externally coupling a portion of the induced light from the optical waveguide using a multi-beam element to provide a plurality of tilted rays having different principal maximal angular directions, each corresponding to a different viewing direction of the multi-view display. Including
The plurality of tilted rays have an inclination toward the center of the visual field zone of the multi-view display to provide a convergent view, so that the central axes of the plurality of inclined rays intersect the center of the visual field zone by the inclination. How to be set to. The method of operating a multi-view backlight according to claim 20, wherein the size of the multi-beam element is equivalent to the size of a sub-pixel in the multi-view pixel of the multi-view display. The method of operating a multi-view backlight according to claim 20, wherein the multi-beam element includes a diffraction grating that is optically coupled to the optical waveguide and diffractically externally couples a part of the induced light. Select the inter-element distance between pairs of multi-beam elements that is greater than the inter-pixel distance between the corresponding pairs of multi-view pixels in the multi-view display, and / or select the greater inter-element distance and / or By changing the scattering characteristics of the multi-beam elements in the array of multi-beam elements arranged along the length of the optical waveguide according to the position of the multi-beam elements in the array of the multi-beam elements, the plurality of said. The method of operating a multi-view backlight according to claim 20, further comprising the step of providing the inclination of the inclined light beam. It further comprises the step of providing light to the optical waveguide using a light source, wherein the provided light has a non-zero propagation angle within the optical waveguide or is collimated according to a collimation factor of the induced light. The method of operating a multi-view backlight according to claim 20, which is an induced light that provides diffusion at a predetermined angle, or both. The operation of the multi-view backlight according to claim 20, further comprising a step of modulating a light ray among the plurality of inclined light rays by using a plurality of light valves configured as multi-view pixels of the multi-view display. Method.